Method for fabricating wiring board provided wiht passive element, and wiring board provided with passive element

ABSTRACT

A fabricating method of a wiring board provided with passive elements is disclosed. The fabricating method includes coating one or both of resistive paste and dielectric paste on at least any one of first surfaces of a first metal foil and a second metal foil each of which has a first surface and a second surface; arranging an insulating board having thermo-plasticity and thermo-setting properties so as to face the first surface of the first metal foil, and arranging the first surface side of the second metal foil so as to face a surface different from a surface to which the first metal foil faces of the insulating board; forming a double-sided wiring board by stacking, pressurizing and heating the arranged first metal foil, insulating board, and second metal foil, and thereby integrating these; and patterning the first metal foil and/or the second metal foil.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a method for fabricating awiring board provided with a passive element and to a wiring boardprovided with a passive element, in particular to a method forfabricating a wiring board provided with a passive element having anaptitude for improving characteristics of the passive element and to awiring board provided with a passive element having an aptitude forimproving characteristics of the passive element.

[0003] 2. Description of the Related Art

[0004] As portable electronic devices become smaller in size, lighter inweight and thinner in thickness, smaller size chip components, such as L(inductor, coil), C (condenser, capacitor) and R (resistor), have beendeveloped. Furthermore, by burying passive elements such as C and L in awiring substrate, composite components have been developed. Suchintegration with a wiring substrate has been actively forwardedparticularly in multi-layered ceramic substrates and adopted in, forinstance, RF (radio frequency) modules for portable telephones.

[0005] A multi-layered ceramic substrate is fabricated by firstpreparing a necessary number of green sheets (ceramic material sheetbefore sintering) on which coil patterns and capacitor electrodepatterns are formed by, for instance, printing a thick film of aconductive paste, followed by stacking these in a predetermined orderand by performing simultaneous thermo-compression bonding and sintering.

[0006] Furthermore, a plurality of green sheets having differentdielectric constants is prepared, and according to characteristics of apassive component to be incorporated, the green sheets are appropriatelyselected. This is performed by selecting a low dielectric constant greensheet that can set a high self-resonant frequency and secure a highQ-value for a ceramic material that constitutes an inductor, and a highdielectric constant green sheet for a ceramic layer that forms acapacitor, respectively. By use of such a combination, an LC compositecomponent having higher function may be incorporated.

[0007] In the aforementioned technique, ceramics is used for wiringsubstrate material. It is expected that in future an operating frequencyof an RF circuit that is used in a portable telephone may reach 10 to 20GHz. In view of this, it is important from a viewpoint of product costsand so on that organic resins having lower relative dielectric constantsare made available as the substrate material. As things are, when anorganic resin that is lower in dielectric constant than the ceramics isused as a substrate material (inter-layer insulating layer), and passiveelements such as capacitors and so on are incorporated similarly to themultilayer ceramic substrate, it is supposed that an element area maybecome larger and desired characteristics may not be obtained.

[0008] Furthermore, as to the so-called hybrid multi-layered substrates,there are the following reports. That is, first, according tocharacteristics of a passive element to be incorporated, a substratematerial in which a dielectric material and a magnetic material aremingled with polymer is prepared. Thus obtained substrate material isetched, and thereby a patterned capacitor layer and a coil layer areformed. These are laminated in a predetermined order, and thereby ahybrid multi-layered substrate is obtained.

[0009] However, in this technique, the multi-layered substrate may warpdue to the difference of characteristics such as thermal expansioncoefficient and so on between the substrate materials. In addition,since only one specified kind of passive element may be formed in onelayer, a design allowance when the passive elements are arranged is low.That is, it is inappropriate in obtaining a smaller size due to tendencyto an increase in the number of layers as a whole.

[0010] Furthermore, there is another multi-layered organic resinsubstrate in which resistive paste, dielectric paste, and conductivepaste are sequentially printed to incorporate R, L and C. However, sincethe paste that can be used in this case is restricted to kinds thatallow completing heat treatment at temperatures lower than the heatresistance temperature of an organic resin that is used as an insulatinglayer, the desired characteristics may not be obtained in some cases.

SUMMARY OF THE INVENTION

[0011] The present invention is carried out in consideration of theaforementioned situations. That is, the present invention provides amethod for fabricating a wiring board that is provided with passiveelements having improved characteristics, and a wiring board that isprovided with such passive elements.

[0012] A method for fabricating a wiring board provided with a passiveelement according to the present invention includes coating a resistivepaste and/or a dielectric paste on at least any one of first surfaces ofa first metal foil and a second metal foil each of which has the firstsurface and a second surface; arranging an insulating board havingthermo-plasticity and thermo-setting properties so as to face the firstsurface of the first metal foil, and arranging the first surface side ofthe second metal foil so as to face a surface different from a surfaceto which the first metal foil faces of the insulating board; forming adouble-sided wiring board by stacking, pressurizing and heating three,that is, the arranged first metal foil, insulating board, and secondmetal foil and thereby integrating these; and patterning the first metalfoil and/or the second metal foil of the formed double-sided wiringboard.

[0013] That is, resistive paste and dielectric paste are coated on ametal foil. Accordingly, these pastes can be heat-treated (such as, forinstance, drying, sintering, and curing) irrespective of the heatresistance temperature of an insulating board. Thereafter, the metalfoil having thus, for instance, heat-treated resistive element anddielectrics and the insulating board are laminated. Accordingly, awiring board provided with passive elements having excellentcharacteristics can be obtained.

[0014] Furthermore, another method for fabricating a wiring boardprovided with a passive element according to the present inventionincludes coating a resistive paste on a first surface of at least afirst metal foil of the first metal foil and a second metal foil each ofwhich has the first surface and a second surface; forming asubstantially conical conductive bump on a resistive element formed ofthe coated resistive paste; arranging an insulating board havingthermo-plasticity and thermosetting properties so as to face the firstsurface of the first metal foil, and arranging the first surface of thesecond metal foil so as to face a surface different from a surface towhich the first metal foil faces of the insulating board; forming adouble-sided wiring board by stacking, pressurizing and heating three,that is, the arranged first metal foil, insulating board, and secondmetal foil and thereby integrating these so that the formed conductivebump may penetrate through the insulating board and establish anelectrical contact and/or a heat conductive contact with the secondmetal foil; and patterning the first metal foil and the second metalfoil of the formed double-sided wiring board.

[0015] That is, a resistive paste is coated on a metal foil.Accordingly, the heat-treatment (such as, for instance, drying,sintering, and curing) and so on of the paste can be performedirrespective of the heat resistance temperature of an insulating board.Thereafter, the metal foil having thus, for instance, heat-treated paste(resistive element) and the insulating board are laminated. Accordingly,a wiring board provided with passive elements (resistors in this case)having excellent characteristics can be obtained.

[0016] Furthermore, in this case, the wiring board may be configured sothat the conductive bump may directly establish one or both of anelectrical contact and a heat conductive contact with the coated/formedresistive element. Accordingly, since a lead wire can be pulled out ofthe resistive element while avoiding a contact between the resistiveelement and the metal foil, the resistive paste that is less compatiblewith a metal (for instance, copper) that is used for the metal foil maybe used. Accordingly, by further expanding a range of choice ofavailable resistive pastes, a wiring board provided with a passiveelement having excellent characteristics may be obtained. Furthermore,when the conductive bump is brought into a heat conductive contact withthe resistive element, for instance, a heat sink may be disposed on arear surface side (an opposite side from a surface side having aresistor thereon) of the insulating board.

[0017] Still furthermore, still another method for fabricating a wiringboard provided with a passive element according to the present inventionincludes coating a dielectric paste on a first surface of at least asecond metal foil of a first metal foil and the second metal foil eachof which has the first surface and a second surface; coating aconductive paste so as to include on the coated dielectric paste andextend onto the first surface on which the dielectric paste is coated;arranging an insulating board having thermo-plasticity and thermosettingproperties so as to face the first surface of the first metal foil, andarranging the first surface of the second metal foil so as to face asurface different from a surface to which the first metal foil faces ofthe insulating board; forming a double-sided wiring board by stacking,pressurizing and heating three, that is, the arranged first metal foil,insulating board, and second metal foil and thereby integrating these;and patterning at least the second metal foil of the formed double-sidedwiring board.

[0018] That is, a dielectric paste is coated on a metal foil.Accordingly, heat-treatment (such as, for instance, drying, sintering,and curing) and so on of the paste can be performed irrespective of theheat resistance temperature of an insulating board. Thereafter, themetal foil having thus, for instance, heat-treated paste (dielectricmaterial) and the insulating board are laminated. Accordingly, a wiringboard provided with a passive element (capacitor in this case) havingexcellent characteristics can be obtained.

[0019] Furthermore, in this case, furthermore, an electrical conductorformed of the conductive paste and the metal foil may sandwichdielectrics, thereby a so-called parallel plate capacitor is formed.Thereby, a capacitor having higher capacitance may be formed.

[0020] Still furthermore, still another method for fabricating a wiringboard provided with a passive element according to the present inventionincludes coating a dielectric paste on a first surface of at least asecond metal foil of a first metal foil and the second metal foil eachof which has the first surface and a second surface; coating a firstconductive paste so as to contain on the coated dielectric paste and toextend onto the first surface on which the dielectric paste is coated;coating a second dielectric paste so as to contain on the coated firstconductive paste; coating a second conductive paste so as to contain onthe coated second dielectric paste, to extend onto the first surface onwhich the second dielectric paste is coated, and not to come intocontact with the first conductive paste; arranging an insulating boardhaving thermo-plasticity and thermosetting properties so as to face thefirst surface of the first metal foil, and arranging the first surfaceof the second metal foil so as to face a surface different from asurface to which the first metal foil faces of the insulating board;forming a double-sided wiring board by stacking, pressurizing andheating three, that is, the arranged first metal foil, insulating board,and second metal foil, and thereby integrating these; and patterning atleast the second metal foil of the formed double-sided wiring board.

[0021] That is, a dielectric paste and a conductive paste are coated ona metal foil. Thereby, heat treatment (for instance, drying, sintering,and curing) of the pastes may be performed irrespective of the heatresistance temperature of an insulating board. Since the metal foilhaving thus, for instance, heat-treated paste (dielectric material) islaminated together with the insulating board, a wiring board providedwith a passive element (capacitor in this case) excellent incharacteristics can be obtained.

[0022] In this case, furthermore, since an electrical conductor made ofthe conductive paste and the metal foil may be formed to sandwich thedielectrics, and the electrical conductor and an electrical conductormade of the second conductive paste may be formed to sandwich the seconddielectrics, a so-called parallel plate capacitor may be formed inmulti-layers. Thereby, a capacitor having higher capacitance may beformed. Such a multi-layered capacitor, by forming dielectrics and anelectrical conductor in a further multi-layered structure due to thedielectric paste and conductive paste, may be provided with furthermorehigher capacitance.

[0023] Furthermore, still another method for fabricating a wiring boardprovided with a passive element according to the present inventionincludes forming a substantially conical conductive bump on a firstsurface of a first metal foil having the first surface and a secondsurface; forming a substantially conical magnetically permeable bump ona first surface of a second metal foil having the first surface and asecond surface; arranging an insulating board having thermo-plasticityand thermosetting properties so as to face the first surface of thefirst metal foil, and arranging the first surface side of the secondmetal foil so as to face a surface different from a surface to which thefirst metal foil faces of the insulating board; forming a double-sidedwiring board by stacking, pressurizing and heating three, that is, thearranged first metal foil, insulating board, and second metal foil, andthereby integrating these so that the formed conductive bump andmagnetically permeable bump may penetrate through the insulating boardand establish a contact with the first or second metal foil; andpatterning the first metal foil and the second metal foil of the formeddouble-sided wiring board.

[0024] That is, a conductive bump and a magnetically permeable bump areformed on a metal foil. Accordingly, the bumps can be heat-treated (suchas, for instance, drying, sintering, and curing) irrespective of theheat resistance temperature of an insulating board. Thereafter, themetal foil having thus, for instance, heat-treated bump and theinsulating board are laminated. Accordingly, a wiring board providedwith a passive element (in this case inductor) having excellentcharacteristics may be obtained.

[0025] Furthermore, in this case, furthermore, due to patterning of afirst and second metal layers and due to an electrical connectionbetween these by means of a conductive bump, a helical inductor with themagnetically permeable bump as a core may be formed. Accordingly, oneshaving larger inductance may be formed.

[0026] A wiring board provided with a passive element according to thepresent invention includes an insulating board having a first surfaceand a second surface; a layered resistive element and/or a layereddielectrics disposed on the first surface and/or the second surface ofthe insulating board so as to sink in a thickness direction of theinsulating board; and a first wiring layer and a second wiring layerthat are, respectively, disposed on the first surface and the secondsurface of the insulating board, and each of which has a connection withthe layered resistive element/the layered dielectrics disposed on thecorresponding first surface/second surface.

[0027] Furthermore, another wiring board provided with a passive elementaccording to the present invention includes an insulating board having afirst surface and a second surface; a layered resistive element disposedon the second surface of the insulating board so as to sink in athickness direction of the insulating board; a first and second wiringlayers disposed on the first surface and second surface of theinsulating board, respectively; and a conductive bump that penetratesthrough the insulating board and is in an electrical connection and/or aheat conductive connection with the layered resistive element and thefirst wiring layer.

[0028] Still furthermore, still another wiring board provided with apassive element according to the present invention includes aninsulating board having a first surface and a second surface; a layeredelectrical conductor disposed on the second surface of the insulatingboard so as to sink in a thickness direction of the insulating board; alayered dielectrics disposed in partial contact with a top surface ofthe layered electrical conductor so as to sink in a thickness directionof the insulating board; and a wiring layer that is disposed on thesecond surface of the insulating board and has individual connectionswith the layered electrical conductor and the layered dielectrics.

[0029] Furthermore, still another wiring board provided with a passiveelement according to the present invention includes an insulating boardhaving a first surface and a second surface; a first and second wiringlayers, respectively, disposed on the first surface and the secondsurface of the insulating board; a conductive bump that penetratesthrough the insulating board and is in an electrical connection with thefirst wiring layer and the second wiring layer; and a magneticallypermeable bump that penetrates through the insulating board. In theabove, the first wiring layer has a first pattern that surrounds themagnetically permeable bump, the second wiring layer has a secondpattern that surrounds the magnetically permeable bump, and the firstand second patterns are in an electrical continuity due to theconductive bump.

[0030] The wiring boards are ones that can be fabricated by theaforementioned respective fabricating methods.

BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The invention is described with reference to the drawings, whichare presented for the purpose of illustration only and do not limit thescope of the invention.

[0032]FIG. 1A and FIG. 1B are diagrams showing a process for fabricatinga double-sided wiring board according to a fabricating method accordingto an embodiment of the present invention.

[0033]FIG. 2A and FIG. 2B are diagrams showing a process for fabricatinga double-sided wiring board according to a fabricating method accordingto another embodiment of the present invention.

[0034]FIG. 3 is a perspective view showing an example of thedouble-sided wiring board fabricated by the process shown in FIG. 1A andFIG. 1B, or FIG. 2A and FIG. 2B.

[0035]FIG. 4A and FIG. 4B are diagrams showing a process for making thedouble-sided wiring board that is fabricated by the process shown inFIG. 1A and FIG. 1B, or FIG. 2A and FIG. 2B into a material of athree-layered or four-layered material.

[0036]FIG. 5A and FIG. 5B are diagrams showing a metal foil necessarywhen the three-layered wiring board or four-layered wiring board isfabricated by use of the double-sided wiring board that is fabricated bythe process shown in FIG. 1A and FIG. 1B, or FIG. 2A and FIG. 2B, and aprocess applied thereon.

[0037]FIG. 6 includes diagrams showing a process for fabricating thefour-layered wiring board by use of a wiring board material that isfabricated by the process shown in FIG. 4A and FIG. 4B, and the metalfoil shown in FIG. 5A and FIG. 5B.

[0038]FIG. 7 includes perspective views showing the process shown inFIG. 6.

[0039]FIG. 8 is a perspective view showing the four-layered wiring boardfabricated according to the fabricating method shown in FIG. 6 (FIG. 7)and having a loop antenna in an outer wiring.

[0040]FIG. 9 is a partial sectional view as an example of a double-sidedwiring board fabricated according to the fabricating method according tostill another embodiment of the present invention.

[0041]FIG. 10 is a bottom view of the double-sided wiring board shown inFIG. 9.

[0042]FIG. 11 is a partial sectional view showing another example to theexample shown in FIG. 9.

[0043]FIG. 12A and FIG. 12B are partial sectional views for explainingan example of a double-sided wiring board fabricated according to thefabricating method according to still another embodiment of the presentinvention.

[0044]FIG. 13A and FIG. 13B are partial sectional views for explaininganother example to the example shown in FIG. 12A and FIG. 12B.

[0045]FIG. 14A and FIG. 14B are diagrams for explaining irregularity inthe shape at a periphery of the dielectrics/resistive element/electricalconductor coated on the metal foil and an improvement thereof.

[0046]FIG. 15A and FIG. 15B are diagrams for explaining an example of afour-layered wiring board fabricated according to the fabricating methodaccording to still another embodiment of the present invention.

[0047]FIG. 16A and FIG. 16B are diagrams for explaining another exampleto the example shown in FIG. 15A and FIG. 15B.

DETAILED DESCRIPTION OF THE INVENTION

[0048] The fabricating method according to the present invention, as animplementation mode, further includes forming a substantially conicalconductive bump on the first surface of the first metal foil. In thiscase, the forming a double-sided wiring board is performed so that theformed conductive bump may penetrate through the insulating board andestablish an electrical contact with the second metal foil. That is,since wiring layers on both sides are electrically connected by means ofa conductive bump, the number of the processes may be reduced and adouble-sided wiring board whose wiring layers on both sides have anelectrical continuity may be easily fabricated.

[0049] Furthermore, in an implementation mode of the fabricating methodaccording to the present invention, the patterning the first metal foiland/or the second metal foil includes the formation of an inductor thatis vortically formed due to a pattern and/or a loop antenna that isformed loop-like due to a pattern. That is, an inductor and a loopantenna are formed by patterning a metal foil.

[0050] Still furthermore, the fabricating method according to thepresent invention further includes trimming a resistor formed from theresistive paste by use of the patterned first metal foil and/or thepatterned second metal foil as an electrode. That is, since an electrodecan be formed to a resistor due to the patterning, by making use thereoffor resistance measurement, is the resistor trimmed.

[0051] Furthermore, in an implementation mode of the fabricating methodaccording to the present invention, the coating the resistive pasteand/or the dielectric paste includes removing a periphery portionthereof after the coating. By removing irregularity at the edge portionsof the coated resistive element and dielectrics, the resistor andcapacitor having higher accuracy may be obtained.

[0052] Still furthermore, the fabricating method according to thepresent invention, as an implementation mode, further includes forming asubstantially conical conductive bump on a first surface of a thirdmetal foil having the first surface and a second surface; arranging asecond insulating board having thermo-plasticity and thermosettingproperties so as to face the first surface of the third metal foil, andarranging the first metal foil side of the double-sided wiring board soas to face a surface different from a surface that faces the third metalfoil of the second insulating board; forming a three-layered wiringboard by stacking, pressurizing and heating three, that is, the arrangedthird metal foil, second insulating board, and double-sided wiringboard, and thereby integrating these so that the conductive bump formedon the third metal foil may penetrate through the second insulatingboard and establish an electrical contact with the first metal foil; andpatterning the third metal foil of the formed three-layered wiringboard.

[0053] That is, by use of a double-sided wiring board as a material, andby further establishing an interlayer connection with a third wiringlayer due to a conductive bump, a three-layered wiring board isfabricated.

[0054] Still furthermore, the fabricating method according to thepresent invention, as an implementation mode, further includes coating aresistive paste and/or a dielectric paste on a first surface of a thirdmetal foil having the first surface and a second surface; forming asubstantially conical conductive bump on the first surface of the thirdmetal foil; arranging a second insulating board having thermo-plasticityand thermosetting properties so as to face the first surface of thethird metal foil, and arranging a first metal foil side of thedouble-sided wiring board so as to face a surface different from asurface that faces the third metal foil of the second insulating board;forming a three-layered wiring board by stacking, pressurizing andheating three, that is, the arranged third metal foil, second insulatingboard, and double-sided wiring board, and thereby integrating these sothat the conductive bump formed on the third metal foil may penetratethrough the second insulating board and establish an electrical contactwith the first metal foil; and patterning the third metal foil of theformed three-layered wiring board.

[0055] That is, by use of a double-sided wiring board as a material, byfurther establishing an interlayer connection with a third wiring layerdue to a conductive bump, a three-layered wiring board is fabricated.Here, a passive element may be enabled to use in the third wiring layer.

[0056] Furthermore, the fabricating method according to the presentinvention, as an implementation mode, further includes forming asubstantially conical conductive bump on the second surface of thesecond metal foil of the formed double-sided wiring board; arranging asecond insulating board having thermo-plasticity and thermosettingproperties so as to face a side on which the conductive bump of thedouble-sided wiring board is formed, and arranging a third metal foil soas to face a surface different from a surface that faces thedouble-sided wiring board of the second insulating board; forming athree-layered wiring board by stacking, pressurizing and heating three,that is, the arranged double-sided wiring board, second insulatingboard, and third metal foil, and thereby integrating these so that theconductive bump formed on the double-sided wiring board may penetratethrough the second insulating board and establish an electrical contactwith the third metal foil; and patterning the third metal foil of theformed three-layered wiring board.

[0057] Also in this case, with a double-sided wiring board as amaterial, by further use of a conductive bump, an interlayer connectionwith a third wiring board is established, thereby forming athree-layered wiring board.

[0058] Still furthermore, the fabricating method according to thepresent invention, as an implementation mode, further includes coating aresistive paste and/or a dielectric paste on a first surface of a thirdmetal foil having the first surface and a second surface; forming asubstantially conical conductive bump on the second surface of thesecond metal foil of the formed double-sided wiring board; arranging asecond insulating board having thermo-plasticity and thermosettingproperties so as to face a side on which the conductive bump of thedouble-sided wiring board is formed, and arranging the first surfaceside of the third metal foil so as to face a surface different from asurface that faces the double-sided wiring board of the secondinsulating board; forming a three-layered wiring board by stacking,pressurizing and heating three, that is, the arranged double-sidedwiring board, second insulating board, and third metal foil, and therebyintegrating these so that the conductive bump formed on the double-sidedwiring board may penetrate through the second insulating board andestablish an electrical contact with the third metal foil; andpatterning the third metal foil of the formed three-layered wiringboard.

[0059] In this case too, by use of a double-sided wiring board as amaterial, by further establishing an interlayer connection with a thirdwiring layer due to a conductive bump, a three-layered wiring board isfabricated. Here, a passive element may be enabled to use in the thirdwiring layer.

[0060] Furthermore, in an implementation mode of the fabricating methodaccording to the present invention, the patterning the third metal foilincludes the formation an inductor that is vortically formed due to apattern and/or a loop antenna that is formed loop-like due to a pattern.That is, by patterning the third metal foil, an inductor and a loopantenna may be formed.

[0061] Still furthermore, in an implementation mode of the fabricatingmethod of the present invention, the coating a resistive paste and/or adielectric paste on the first surface of the third metal foil includesremoving a periphery portion thereof after the coating. This is aprocess to obtain a resistive element and dielectrics having higheraccuracy from a resistive paste and dielectric paste coated on a thirdmetal foil.

[0062] Furthermore, the fabricating method according to the presentinvention, as an implementation mode, further includes forming asubstantially conical conductive bump on a first surface of a thirdmetal foil having the first surface and a second surface; forming asubstantially conical second conductive bump on the second surface ofthe second metal foil of the formed double-sided wiring board; arranginga second insulating board having thermo-plasticity and thermosettingproperties so as to face the first surface of the third metal foil,arranging the first metal foil side of the double-sided wiring board soas to face a surface different from a surface to which the third metalfoil faces of the second insulating board, arranging a third insulatingboard having thermo-plasticity and thermosetting properties so as toface a side on which the second conductive bump is formed of thedouble-sided wiring board, and arranging the fourth metal foil so as toface a surface different from a surface that faces the double-sidedwiring board of the third insulating board; forming a four-layeredwiring board by stacking, pressurizing and heating five, that is, thearranged third metal foil, second insulating board, double-sided wiringboard, third insulating board, and fourth metal foil, and therebyintegrating these so that the conductive bump formed on the third metalfoil may penetrate through the second insulating board and establish anelectrical contact with the first metal foil and the second conductivebump formed on the double-sided wiring board may penetrate through thethird insulating board and establish an electrical contact with thefourth metal foil; and patterning the third metal foil and/or the fourthmetal foil of the formed four-layered wiring board.

[0063] That is, by use of a double-sided wiring board as a material, byestablishing an interlayer connection between the third and fourthwiring layers due to a conductive bump, a four-layered wiring board isfabricated.

[0064] Still furthermore, the fabricating method according to thepresent invention, as an implementation mode, further includes coating aresistive paste and/or a dielectric paste on at least any one of firstsurfaces of a third and fourth metal foils each of which has the firstsurface and a second surface; forming a substantially conical conductivebump on the first surface of the third metal foil; forming asubstantially conical second conductive bump on the second surface ofthe second metal foil of the formed double-sided wiring board; arranginga second insulating board having thermo-plasticity and thermosettingproperties so as to face the first surface of the third metal foil,arranging the first metal foil side of the double-sided wiring board soas to face a surface different from a surface to which the third metalfoil faces of the second insulating board, arranging a third insulatingboard having thermo-plasticity and thermosetting properties so as toface a side on which the second conductive bump is formed of thedouble-sided wiring board, and arranging the first surface side of thefourth metal foil so as to face a surface different from a surface thatfaces the double-sided wiring board of the third insulating board;forming a four-layered wiring board by stacking, pressurizing andheating five, that is, the arranged third metal foil, second insulatingboard, double-sided wiring board, third insulating board, and fourthmetal foil, and thereby integrating these so that the conductive bumpformed on the third metal foil may penetrate through the secondinsulating board and establish an electrical contact with the firstmetal foil and the second conductive bump formed on the double-sidedwiring board may penetrate through the third insulating board andestablish an electrical contact with the fourth metal foil; andpatterning the third metal foil and/or the fourth metal foil of theformed four-layered wiring board.

[0065] Also in this case, by use of a double-sided wiring board as amaterial, by further establishing an interlayer connection with a thirdand fourth wiring layer due to a conductive bump, a four-layered wiringboard is fabricated. Even in the third and fourth wiring layers, passiveelements may be utilized.

[0066] Furthermore, in an implementation mode of the fabricating methodaccording to the present invention, the patterning the third metal foiland/or the fourth metal foil includes the formation of an inductor thatis vortically formed due to a pattern and/or a loop antenna that isformed loop-like due to a pattern. That is, by patterning a third metalfoil and a fourth metal foil, an inductor and a loop antenna may beformed.

[0067] Still furthermore, in an implementation mode of the fabricatingmethod of the present invention, the coating a resistive paste and/or adielectric paste on at least any one of the first surfaces of the thirdand fourth metal foils includes removing a periphery portion thereofafter the coating. This is a process for obtaining a resistive elementand/or dielectrics having higher accuracy from the resistive paste andthe dielectric paste coated on the third metal foil and/or the fourthmetal foil.

[0068] Furthermore, the fabricating method according to the presentinvention, as an implementation mode, further includes forming asubstantially conical second conductive bump on a first surface of athird metal foil having the first surface and a second surface; forminga substantially conical second magnetically permeable bump on a firstsurface of a fourth metal foil having the first surface and a secondsurface; forming a substantially conical third conductive bump on thesecond surface of the second metal foil of the formed double-sidedwiring board; forming a substantially conical third magneticallypermeable bump on a surface of the first metal foil side of the formeddouble-sided wiring board; arranging a second insulating board havingthermo-plasticity and thermosetting properties so as to face the firstsurface of the third metal foil, arranging a first metal foil side ofthe double-sided wiring board so as to face a surface different from asurface to which the third metal foil faces of the second insulatingboard, arranging a third insulating board having thermo-plasticity andthermosetting properties so as to face a side on which the thirdconductive bump is formed of the double-sided wiring board, andarranging the first surface side of a fourth metal foil so as to face asurface different from a surface that faces the double-sided wiringboard of the third insulating board; forming a four-layered wiring boardby stacking, pressurizing and heating five, that is, the arranged thirdmetal foil, second insulating board, double-sided wiring board, thirdinsulating board, and a fourth metal foil, and thereby integrating theseso that the second conductive bump formed on the third metal foil maypenetrate through the second insulating board and establish anelectrical contact with the first metal foil, the second magneticallypermeable bump formed on the double-sided wiring board may penetratethrough the second insulating board and establish a contact with thethird metal foil, the third conductive bump formed on the double-sidedwiring board may penetrate through the third insulating board andestablish an electrical contact with the fourth metal foil, and thethird magnetically permeable bump formed on the fourth metal foil maypenetrate through the third insulating board and establish a contactwith a surface of the second metal foil side of the double-sided wiringboard; and patterning the third metal foil and the fourth metal foil ofthe formed four-layered wiring board.

[0069] That is, by use of a magnetically permeable bump as a core, ahelical inductor is attempted to form in the four-layered wiring board.

[0070] Furthermore, the fabricating method according to the presentinvention, as an implementation mode, further includes forming athrough-hole in a formed double-sided wiring board and filling amagnetically permeable material in the formed through-hole. In place ofthe magnetically permeable bump, a pillar-like body formed by filling amagnetically permeable material in a through-hole may be used as a coreof a helical inductor.

[0071] Furthermore, the fabricating method according to the presentinvention is a fabricating method of a wiring board provided with apassive element that, as an implementation mode, further includesforming a substantially conical conductive bump on the first surface ofthe first metal foil, and the forming a double-sided wiring board isperformed so that the formed conductive bump may penetrate through theinsulating board and establish an electrical contact with the secondmetal foil. The present fabricating method further includes forming asubstantially conical second conductive bump on a first surface of athird metal foil having the first surface and a second surface; forminga substantially conical third conductive bump on the second surface ofthe second metal foil of the formed double-sided wiring board; arranginga second insulating board having thermo-plasticity and thermosettingproperties so as to face the first surface of the third metal foil,arranging the first metal foil side of the double-sided wiring board soas to face a surface different from a surface to which the third metalfoil faces of the second insulating board, arranging a third insulatingboard having thermo-plasticity and thermosetting properties so as toface a side on which the third conductive bump is formed of thedouble-sided wiring board, and arranging the fourth metal foil so as toface a surface different from a surface that faces the double-sidedwiring board of the third insulating board; forming a four-layeredwiring board by stacking, pressurizing and heating five, that is, thearranged third metal foil, second insulating board, double-sided wiringboard, third insulating board, and fourth metal foil, and therebyintegrating these so that the second conductive bump formed on the thirdmetal foil may penetrate through the second insulating board andestablish an electrical contact with the first metal foil and the thirdconductive bump formed on the double-sided wiring board may penetratethrough the third insulating board and establish an electrical contactwith the fourth metal foil; patterning the third metal foil and thefourth metal foil of the formed four-layered wiring board; forming athrough-hole in the formed four-layered wiring board; and filling amagnetically permeable material in the formed through-hole.

[0072] In this case too, in place of the magnetically permeable bump, apillar-like body that is formed by filling a magnetically permeablematerial in a through-hole is attempted to use as a core of a helicalinductor. The wiring board has a four-layered wiring layer.

[0073] Furthermore, the wiring board according to the present invention,as an implementation mode, further includes a conductive bump thatpenetrates through the insulating board, wherein each of the first andsecond wiring layers has an electrical connection with the conductivebump. That is, since the electrical connection between the wiring layerson both sides is performed by use of a conductive bump, the presentwiring board is a wiring board whose both wiring layers have anelectrical continuity and enables to reduce the number of processes,that is, to realize higher productivity.

[0074] Furthermore, as an implementation mode of the wiring boardaccording to the present invention, at least one of the first and secondwiring layers has an inductor that is vortically formed due to a patternand/or a loop antenna that is formed loop-like due to a pattern. Thatis, an inductor and a loop antenna are formed as a metal foil pattern.

[0075] Still furthermore, a wiring board according to the presentinvention, as an implementation mode, further includes a secondinsulating board disposed in contact with the first wiring layer side ofthe insulating board; a conductive bump that penetrates through thesecond insulating board; and a third wiring layer disposed on a sidedifferent from the insulating board side of the second insulating board;wherein the first wiring layer of the insulating board is disposed so asto sink in a thickness direction of the second insulating board; andeach of the first and third wiring layers has an electrical connectionwith the conductive bump. This is a three-layered wiring board thatcontains a double-sided wiring board inside thereof and in which aninterlayer connection with a third wiring layer is established by meansof a conductive bump.

[0076] Still furthermore, a wiring board according to the presentinvention, as an implementation mode, further includes a second layeredresistive element and/or a second layered dielectrics disposed on thethird wiring layer side of the second insulating board so as to sink ina thickness direction of the second insulating board; wherein the thirdwiring layer has a connection with the second layered resistiveelement/the second layered dielectrics. Thereby, a passive element ismade available even in a third wiring layer.

[0077] Furthermore, as an implementation mode of a wiring boardaccording to the present invention, the third wiring layer has aninductor that is vortically formed due to a pattern and/or a loopantenna that is formed loop-like due to a pattern. That is, an inductorand a loop antenna are formed as a metal foil pattern.

[0078] Still furthermore, a wiring board according to the presentinvention further includes, as an implementation mode, a thirdinsulating board disposed in contact with the second wiring layer sideof the insulating board; a second conductive bump that penetratesthrough the third insulating board; and a fourth wiring layer disposedon a side different from the insulating board side of the thirdinsulating board; wherein the second wiring layer of the insulatingboard is disposed so as to sink in a thickness direction of the thirdinsulating board; and each of the second and fourth wiring layers has anelectrical connection with the second conductive bump. This is afour-layered wiring board that contains a double-sided wiring board as acore wiring board and in which interlayer connections with third andfourth wiring layers are further implemented by means of conductivebumps.

[0079] Still furthermore, a wiring board according to the presentinvention further includes, as an implementation mode, a second layeredresistive element and/or a second layered dielectrics disposed on thefourth wiring layer side of the third insulating board so as to sink ina thickness direction of the third insulating board; wherein the fourthwiring layer has a connection with the second layered resistiveelement/the second layered dielectrics. Thereby, a passive element ismade available even in third and fourth wiring layers.

[0080] Furthermore, as an implementation mode of a wiring boardaccording to the present invention, the fourth wiring layer has aninductor that is vortically formed due to a pattern and/or a loopantenna that is formed loop-like due to a pattern. That is, an inductorand a loop antenna are formed as a metal foil pattern.

[0081] Still furthermore, a wiring board according to the presentinvention further includes, as an implementation mode, a second layereddielectrics disposed under a bottom surface of the layered electricalconductor and a second electrical conductor that is disposed includingunder the bottom surface of the second layered dielectrics and isbrought into contact with the wiring layer. That is, the present wiringboard includes a multi-layered parallel plate capacitor.

[0082] Furthermore, a wiring board according to the present invention,as an implementation mode, further includes a second insulating boarddisposed on the first wiring layer side of the insulating board; a thirdinsulating board disposed on the second wiring layer side of theinsulating board; a third wiring layer disposed on a different surfaceside from the insulating board of the second insulating board; a fourthwiring layer disposed on a different surface side from the insulatingboard of the third insulating board; a second conductive bump thatpenetrates through the second insulating board and is brought intoelectrical connections with the first wiring layer and the third wiringlayer; a second magnetically permeable bump that penetrates through thesecond insulating board; a third conductive bump that penetrates throughthe third insulating board and is brought into electrical connectionswith the second wiring layer and the fourth wiring layer; and a thirdmagnetically permeable bump that penetrates through the third insulatingboard; wherein the first wiring layer is disposed so as to sink in athickness direction of the second insulating board; the second wiringlayer is disposed so as to sink in a thickness direction of the thirdinsulating board; the magnetically permeable bump, the secondmagnetically permeable bump and the third magnetically permeable bumpare disposed in series; the third wiring layer has a third pattern thatsurrounds the second magnetically permeable bump; the fourth wiringlayer has a fourth pattern that surrounds the third magneticallypermeable bump; the first and third patterns are in an electricalcontinuity due to the second conductive bump; and the second and fourthpatterns are in an electrical continuity due to the third conductivebump.

[0083] That is, by use of a magnetically permeable bump as a core, ahelical inductance is formed in a four-layered wiring board.

[0084] Furthermore, a wiring board according to the present inventionincludes, as an implementation mode, in place of the magneticallypermeable bump, the second magnetically permeable bump, and the thirdmagnetically permeable bump, a pillared body that has a magneticallypermeable material and penetrates through the insulating board, thesecond insulating board, and the third insulating board. That is, inplace of a magnetically permeable bump as a core, a pillar having amagnetically permeable material is used as a core of a helical inductor.

[0085] In the following, embodiments of the present invention will beexplained with reference to the drawings. FIG. 1A and FIG. 1B arediagrams showing a process for fabricating a double-sided wiring boardaccording to one embodiment of the present invention.

[0086] First, as shown in FIG. 1A upper side, a metal foil (a copperfoil, for instance) 1 is prepared. On this metal foil 1, a dielectricpaste is coated to be dielectrics 2 of a passive element (capacitor)necessary as a wiring board. Although a coating method is notparticularly restricted, when, for instance, a screen-printing is used,over an entire surface, as many as necessary may be coated with highproductivity and relatively high accuracy. As a dielectric paste, forinstance, a composite in which powder of barium titanate, a highdielectric material is dispersed in a resinouos binder may be used. Asan example, a dielectric paste CX-16, which is commercially availablefrom ASAHI Kagaku Kenkyusho, may be utilized.

[0087] Furthermore, on the metal foil 1, a resistive paste is coated tobe a resistive element 3 of a passive element (resistor) necessary as awiring board. The coating method of the resistive paste is alsoidentical as that mentioned above. As a resistive paste, for instance, acomposite in which resistive material powder is dispersed in a resinouosbinder may be used. As an example, resistive pastes TU-15-8, TU-50-8, orTU-100-8, which are commercially available from ASAHI Kagaku Kenkyusho,may be utilized.

[0088] It is generally better to separately coat a dielectric paste anda resistive paste followed by separately drying and so on. It is becauseafter the drying, a former coating state, without being interfered, maybe maintained. The processing such as the drying and so on may beperformed, irrespective of a heat resistance temperature of aninsulating board (organic material) to be referred to later, attemperatures adequate for processing each of the dielectric paste andthe resistive paste. Accordingly, since a range of choice of kindsthereof is wide, it contributes in the formation of a passive elementhaving higher accuracy.

[0089] Furthermore, in order to make the resistive element 3 furthermoreaccurate, a method (post-treatment) as shown in FIG. 14A and FIG. 14Bmay be used. FIG. 14A and FIG. 14B are diagrams for explainingirregularity in the shape at a periphery portion of the resistiveelement (/dielectrics/electrical conductor) formed on a metal foil andan improvement thereof. FIG. 14A is a sectional view and FIG. 14B is atop view thereof.

[0090] In the resistive element 3 coated by means of the screen-printingand so on, in general, as shown in FIG. 14A, a shape, such as athickness at the periphery thereof is formed a little differently fromthat of an inside portion (edge effect). Such a thickness variation maycause irregularity in a sheet resistance value (one of characteristicvalue of a resistive element; a resistance value between opposite sidesof a square). Accordingly, edge portions 30 of the resistive element 3are removed when the resistive element 3 is formed on the metal foil 1.In such removal, for instance, laser beam may be used. Since, due tosuch the removal, a thickness is more homogenized, a resistive elementhaving a resistance value closer to that expected from the sheetresistance value may be formed. In the case of the dielectrics 2,accuracy is obtained similarly.

[0091] As mentioned above, a coated and formed metal foil 4 on a surfaceof which the resistive element 3 and the dielectrics 2 are formed isformed. Next, as shown in FIG. 1B upper side, resistive element3/dielectrics 2 sides of two coated and formed metal foils 4 arearranged at a predetermined position necessary as a wiring board so asto face both sides of a prepreg to be an insulating board 5. The prepregis obtained by impregnating a curable resin such as, for instance, epoxyresin in a reinforcing material such as glass fiber. Before curing, itis in a semi-cured state and has thermo-plasticity and thermo-settingproperties.

[0092] Next, as shown in FIG. 1B center, three, that is, thecoated/formed metal foil 4, insulating board 5 and another coated/formedmetal foil 4 are stacked, pressurized and heated and thereby integratingthese, a double-sided wiring board 6 is obtained. In the double-sidedwiring board 6, the dielectrics 2 and the resistive element 3 areintegrated so as to sink in a thickness direction of the insulatingboard 5. This is due to the thermo-plasticity and thermo-settingproperties of the prepreg to be the insulating board 5.

[0093] Next, as shown in FIG. 1B lower side, the metal foils 1 on bothsides are patterned into patterns 1 a necessary as a wiring board. Dueto the patterning, a double-sided wiring board 7 on which at least bothend electrodes of the dielectrics 2 and the resistive element 3 areformed may be obtained. In the patterning, existing methods such as, forinstance, the formation of a mask due to coating of photo-resist andexposure thereof, etching of the metal foil 1 due to the mask, and so onmay be used.

[0094] In addition, the resistive element 3 may be trimmed by use of theboth end electrodes formed by the patterning as resistance valuemeasuring terminals. The trimming is a process in which, for instance,by use of laser light, the resistive element 3 is partially burned andbrought to conform to a predetermined resistance value.

[0095] Although processes following the above are not shown in thedrawings, the formation of solder resist and plating layers including onthe pattern 1 a, mounting of surface-mounting components on the pattern1 a, or flip-chip mounting of semiconductor chips may be implementedaccording to existing methods. Furthermore, as well known, athrough-hole is bored in a double-sided wiring board 7, a conductivelayer is formed on an internal surface thereof, and thereby thedouble-sided wiring board 7 having an electrical continuity between bothwiring layers thereof may be formed. Still furthermore, according to theaforementioned etching of the metal foil 1, a vortical inductor may beformed. In this case, such a through-hole may be utilized as an insideterminal.

[0096] In the aforementioned embodiments, since materials are selectedfrom a wide range of choice and the dielectrics 2 and the resistiveelement 3 are previously formed from the selected materials on the metalfoil 1, on the same layer, a capacitor and resistor excellent incharacteristics may be formed in a mingled state. Furthermore, since anorganic material is used as the insulating board 5, lighter weight maybe realized than in the case of ceramics.

[0097] In the aforementioned explanation, each of the dielectrics 2 tobe a capacitor, and the resistive element 3 to be a resistor is formedby coating a paste-like composite. However, other than this, when avortical inductor is formed, a conductive paste may be previously coatedvortically as a paste-like composite on a metal foil 1.

[0098] Next, a process for fabricating a double-sided wiring boardaccording to a fabricating method according to another embodiment of thepresent invention will be explained with reference to FIG. 2A and FIG.2B. FIG. 2A and FIG. 2B are diagrams showing a process for fabricating adouble-sided wiring board according to a fabricating method according toanother embodiment of the present invention. The same regions as FIG. 1Aand FIG. 1B are given the same reference numerals. Explanation of thesame regions will be omitted.

[0099] This embodiment is different from one shown in FIG. 1A and FIG.1B in that as shown in FIG. 2A lower side, a process in which thecoated/formed metal foil 4 is transformed into a conductive bump formedmetal foil 4 a on which conductive bumps 8 have been formed is added.

[0100] The conductive bump 8 may be formed on a place necessary as awiring board on the coated/formed metal foil 4 a by means of, forinstance, screen printing. For this, as a conductive paste, forinstance, one that is prepared by dispersing metal particles (silver,gold, copper, solder and so on) in a paste-like resin followed by mixinga volatile solvent is coated on the metal foil 4 by means of screenprinting. The conductive bump 8 is necessary to have a height enough topenetrate through the insulating board 5 as will be detailed later.Accordingly, when one time screen-printing cannot give a necessaryheight, by repeating the screen-printing a plurality of times whiledisposing a drying process between the consecutive screen-printings, aheight is increased and thereby forming a substantially conical shape asa whole is performed.

[0101] After the conductive bump formed metal foil 4 a is obtained asshown in the above, next, as shown in FIG. 2B upper side, a resistiveelement 3 and dielectrics 2 side of the coated/formed metal foil 4 isdisposed so as to face one side of both sides of the prepreg to be ainsulating board 5, and a resistive element 3, dielectrics 2 andconductive bump 8 side of the conductive bump formed metal foil 4 a isdisposed so as to face the other side of both sides of the prepreg.

[0102] Next, as shown in FIG. 2B center, a double-sided wiring board 6 ais obtained by stacking, pressurizing and heating three, that is, thecoated/formed metal foil 4, insulating board 5, and conductive bumpformed metal foil 4 a, and thereby integrating these. In thedouble-sided wiring board 6 a, the dielectrics 2 and resistive element 3are integrated so as to sink in a thickness direction of the insulatingboard 5, and the conductive bump 8 penetrates through the insulatingboard 5 and comes into an electrical contact with the opposing metalfoil 1. Such a state is realized because, as mentioned above, theinsulating board 5 had thermo-plasticity and thermo-setting properties,and the conductive bump 8 is originally formed into a substantial cone.

[0103] In the double-sided wiring board 6 a, since an electricalcontinuity between both wiring layers is established by the conductivebump 8, there is no need of a further process such as the formation of athrough-hole to establish an electrical continuity between both wiringlayers. Accordingly, since a space for the formation of the through-holeis not necessary, a wiring board of higher density may be obtained.Furthermore, in the integrating process, since a pressure on thedielectrics 2 and the resistive element 3 may be alleviated by theconductive bump 8 that works as a support, there is an advantageouseffect that dispersions of various characteristics of the dielectrics 2and the resistive element 3 that are caused at the integration may besuppressed.

[0104] Following the above, as shown in FIG. 2B lower side, the metalfoils 1 on both sides are patterned into a pattern 1 a necessary as awiring board (substantially similar to the case of FIG. 1B lower side).Due to the patterning, a double-sided wiring board 7 a in which both endelectrodes of the dielectrics 2 and the resistive element 3 are at leastformed may be obtained. In addition to this, the resistive element 3 maybe trimmed by use of the both end electrodes formed by this patterningas resistance value measurement terminals. This is also as explainedabove.

[0105] Furthermore, although the processes following the above are notshown in the drawings, the formation of solder resist and plating layersincluding on the pattern 1 a, mounting of surface-mounting components onthe pattern 1 a, or flip-chip mounting of semiconductor chips and so onmay be performed according to existing methods. Still furthermore,according to the etching of the metal foil 1 as mentioned above, avortical inductor may be formed. In this case, the above-explainedconductive bump 8 may be utilized as an inside terminal.

[0106] In the above-explained embodiment, similarly to the embodimentexplained in FIG. 1A and FIG. 1B, since materials are selected from alarge choice of materials and the dielectrics 2 and the resistiveelement 3 are formed previously on the metal foil 1, a capacitor andresistor excellent in characteristics may be incorporated in the samelayer in a mingled state. Furthermore, since an organic material is usedas the insulating board 5, lighter weight may be realized than in thecase of ceramics. Furthermore, in order to form a vortical inductor, inadvance the conductive paste may be vortically coated on the metal foil1.

[0107]FIG. 3 is a perspective view showing the double-sided wiring board7 that can be formed according to the embodiment explained in FIG. 1Aand FIG. 1B, or the double-sided wiring board 7 a that can be formedaccording to the embodiment explained in FIG. 2A and FIG. 2B. As shownin FIG. 3, on both sides (one side may be allowed) of the insulatingboard 5, a resistor due to the resistive element 3, a capacitor due tothe dielectrics 2, and a vortical inductor due to the pattern 1 a may beincorporated in a state previously provided to the wiring boards 7/7 a.By making use of the wiring pattern 1 a as a land to mount surface mountcomponents and semiconductor devices on both sides of the double-sidedwiring board 7 a, it may be of course used as a mounted wiring board asit is.

[0108]FIG. 4A and FIG. 4B are diagrams showing a process carried out tomake the double-sided wiring board 7 a (7) that is fabricated accordingto the process shown in FIG. 1A and FIG. 1B, or FIG. 2A and FIG. 2B amaterial of a four-layered wiring board. FIG. 4A is a sectional view,and FIG. 4B is a perspective view. FIG. 5A and FIG. 5B are diagramsshowing a necessary metal foil when a four-layered wiring board isfabricated with the double-sided wiring board 7 a (7) fabricatedaccording to the process shown in FIG. 1A and FIG. 1B, or FIG. 2A andFIG. 2B and a process applied thereon. FIG. 5A is a sectional view, andFIG. 5B is a perspective view. Furthermore, already explained regions inthese figures are given the same reference numerals. An N-layered wiringboard is a wiring board in which the number of the wiring layers is N.

[0109] First, as shown in FIG. 4A and FIG. 4B, in order to use thedouble-sided wiring board 7 a (7) as a core wiring board, conductivebumps 9 are formed on necessary positions on one side thereof (positionsaccording to a layout as a particular four-layered wiring board). Theformation of the conductive bumps 9 may be implemented substantiallysimilarly to the already mentioned formation of the conductive bump 8.Thereby, a wiring board material 71 having the conductive bumps 9 isformed.

[0110] At the same time, as shown in FIG. 5A and FIG. 5B, a metal foil 1to be the third wiring layer is prepared, and at necessary positions onthe single side thereof (positions according to a layout as a particularfour-layered wiring board) the conductive bumps 9 are formed. Theformation of the conductive bumps 9 is performed also similarly to theabove. Thereby, a metal foil 11 having the conductive bumps 9 is formed.

[0111]FIG. 6 includes diagrams showing a process for fabricating afour-layered wiring board by use of the wiring board material 71fabricated by the process shown in FIG. 4A and FIG. 4B and the metalfoil 11 shown in FIG. 5A and FIG. 5B as materials. FIG. 7 includesperspective views showing the process shown in FIG. 6. In FIG. 6 andFIG. 7, the already explained regions are given the same referencenumerals.

[0112] As shown in FIG. 6 upper side and FIG. 7 upper side,respectively, first, the metal foil 1 is disposed through a prepreg tobe an insulating board 51 so as to face a surface on which theconductive bumps 9 are formed of the wiring board material 71, and aside on which the conductive bumps 9 are formed of the metal foil 11 isdisposed through the prepreg to be the insulating board 51 so as to facea surface on which a conductive bump 9 is not formed of the wiring boardmaterial 71. The prepreg to be the insulating board 51 may be onesimilar to the above-mentioned prepreg to be the insulating board 5.

[0113] Next, as shown in FIG. 6 center and FIG. 7 center, a four-layeredwiring board 21 is obtained by stacking, pressurizing and heating five,that is, the metal foil 1, insulating board 51, wiring board material71, insulating board 51, and metal foil 11, and thereby integratingthese. In the double-sided wiring board 21, each of the wiring patterns1 a on both sides of the wiring board material 71 is integrated so as tosink in a thickness direction of the insulating boards 51, and theconductive bumps 9 penetrate through the each of the insulating boards51 and come into an electrical contact with the opposing metal foil 1 orthe pattern 1 a. Such a state is realized because the insulating boards51 had thermo-plasticity and thermo-setting properties, and theconductive bumps 9 are originally formed in substantial cone.

[0114] In the four-layered wiring board 21, since an electricalcontinuity between an outer wiring layer and an inner wiring layer isestablished by means of the conductive bumps 9, there is no need ofperforming a further process such as through-hole formation forestablishing an electrical continuity between these. Accordingly, sincea space for use in through-hole formation is not necessary, a higherdensity four-layered wiring board may be obtained. In addition, in viewof not adversely affecting on the layout of the other layers,needlessness of the through-hole formation is more significant as thenumber of wiring layers increase.

[0115] Next, as shown in FIG. 6 lower side and FIG. 7 lower side, themetal foils 1 on both sides of the four-layered wiring board 21 arepatterned into a pattern 1 b necessary as a wiring board. Due to thepatterning, a four-layered wiring board 22 is formed. In the patterning,as mentioned above, existing methods may be used, and due to thepatterning a vortically shaped inductor may be formed.

[0116] Furthermore, although the processes following the above are notshown by means of the drawings, the formation of solder resist andplating layers including on the pattern 1 b, mounting ofsurface-mounting components on the pattern 1 b, or flip-chip mounting ofsemiconductor chips may be implemented according to existing methods.

[0117] In the above-explained embodiments, an explanation is given for acase where a four-layered wiring board is fabricated with thedouble-sided wiring board 7 a (7) obtained according to the fabricatingmethod that is explained in FIG. 1A and FIG. 1B, or FIG. 2A and FIG. 2Bas a core wiring board. Accordingly, the four-layered wiring board maybe fabricated while maintaining features as the already-explaineddouble-sided wiring board 7 a (7). In addition, since the insulatingboard 51 that is an organic material is used when forming into amulti-layered structure, the formed multi-layered wiring board may bemade lighter than ceramic one.

[0118] In the above explanation, a four-layered wiring board isfabricated by use of the double-sided wiring board 7 a (7). Athree-layered wiring board may be substantially similarly fabricated.That is, as one method, in FIG. 6 upper side, when three from the top(three of metal foil 1, insulating board 51 and wiring board material71) is stacked, pressurized and heated and thereby these are integrated,a three-layered wiring board is obtained. Furthermore, as anothermethod, in FIG. 6 upper side one, by stacking, pressurizing and heatingthree from the bottom (since in this case, the conductive bump 9 on thewiring board material 71 is unnecessary, the three is the wiring boardmaterial 7 a (7), insulating board 51 and metal foil 11), and therebyintegrating these, a three-layered wiring board is obtained.

[0119] Even in such a three-layered wiring board, a three-layered wiringboard may be realized while maintaining features as the above-explaineddouble-sided wiring board 7 a (7).

[0120] Furthermore, in the above explanation, cases where passiveelements are not previously incorporated in the third and fourth wiringlayers of the four-layered wiring board and in the third wiring layer ofthe three-layered wiring board are explained. However, in FIG. 6 upperside one, by use of the coated/formed metal foil 4 (the formationsurface of the passive element is used directed downward) shown in FIG.1A or FIG. 2A in place of the upper side metal foil 1, and by use of theconductive bump formed metal foil 4 a shown in FIG. 2A in place of themetal foil 11, passive elements may be incorporated in the third andfourth wiring layers.

[0121] According to these, the four-layered wiring board 22 may beformed in the shape where the third and fourth wiring layers of thefour-layered wiring board 22 are previously provided with the resistordue to the resistive element 3 and the capacitor due to the dielectrics2. Since the resistors and capacitors with which the third and fourthwiring layers are provided are also previously formed on the metal foil1 before the stacking, there are the advantages similar to the resistorand the capacitor with which the first and second wiring layers areprovided. Furthermore, the resistors with which the third and fourthwiring layers are provided may be also trimmed by use of the pattern 1b. In addition, by previously coating a vortical conductive paste on themetal foil 1, the inductor due to the conductive paste may be formed onthe third and fourth wiring layers.

[0122] Furthermore, when the above-explained method is repeated andused, a wiring board having wiring layers exceeding four layers may beeasily formed. When, for instance, a six-layered wiring board isfabricated, in FIG. 6 upper side one, in place of the wiring boardmaterial 71, one in which the conductive bumps are formed on a singleside of the flour-layered wiring board 22 may be utilized. According tosuch repetition, furthermore multi-layered wiring boards are obtained.

[0123]FIG. 8 is a perspective view showing an example of thefour-layered wiring board fabricated according to the fabricating methodshown in FIG. 6 and FIG. 7. In the four-layered wiring board 22 a inthis example, by use of the pattern 1 b of the outer wiring layer, aland for mounting a semiconductor device 32 and surface-mount componentsis formed, and a loop antenna 31 is formed near an outer periphery ofthe four-layered wiring board 22 a.

[0124] Thereby, the semiconductor device 32, the loop antenna 31 and thepassive elements (ones that are incorporated in the wiring board andsurface-mounted components) necessary for, for example, an IC card(integrated circuit card) that delivers information via radio areintegrated and formed into a four-layered wiring board. The formation ofthe loop antenna 31 by use of such the pattern may be performed by useof the pattern 1 a on the double-sided wiring board 7 (7 a) alreadydescribed in FIG. 1B or FIG. 2B.

[0125]FIG. 9 is a partial sectional view as an example of thedouble-sided wiring board fabricated according to the fabricating methodaccording to still another embodiment of the present invention.Constituent elements that are already explained are given the samereference numerals.

[0126] This double-sided wiring board 7 b is different from one shown inFIG. 2B in that as a lead wire of the resistive element 3, a conductivebump 8 that penetrates through the insulating board 5 is in direct use.In order to fabricate a double-sided wiring board in such aconfiguration, when the metal foil 4 a shown in FIG. 2A is formed, theposition of the conductive bump 8 need only be set so that it may beformed on the resistive element 3 of the metal foil 1.

[0127] Then, as shown in FIG. 2B, these are laminated and followed bypatterning the metal foils 1 on both sides. In the patterning, the metalfoil 1 on a side in contact with the resistive element 3 is patterned sothat the metal foil 1 may not completely come into contact with theresistive element 3.

[0128] In thus configured resistor, since a lead wire thereof is not ametal used in the metal foil 1, without considering compatibility withthe metal a resistive paste to be the resistive element 3 may beselected. The compatibility shows difficulty with which chemical andphysical changes occurs at interfaces of, for instance, the metal (forinstance, copper) of the metal foil 1 and the resistive element 3 whenthese come into contact. Bad compatibility may cause earlier corrosionon any one of these. In the present embodiment, since it is notnecessary to consider the compatibility at least with the metal foil 1,a range of choice of the resistive pastes may be further expanded.Accordingly, further higher precision may be accomplished.

[0129]FIG. 10 is a bottom view as an example of the double-sided wiringboard 7 b shown in FIG. 9. The regions corresponding to FIG. 9 are giventhe same reference numerals.

[0130] As shown in FIG. 10, the contact between the resistive element 3and the conductive bump 8 may occur at a plurality of points (three inthis case shown in the figure) at one end. This is because while a shapeof the resistive element 3 is varied in length and breadth according toa necessary resistance value, the size of the conductive bump 8 isnormally fixed due to the simultaneous formation by use of, forinstance, printing. By use of a plurality number of the conductive bumps8, the lead wires may be drawn out corresponding to the size of theresistive element 3.

[0131]FIG. 11 is a partial sectional view showing another example to oneexample shown in FIG. 9. The constituent elements that are alreadyexplained are given the same reference numerals.

[0132] The double-sided wiring board 7 c is similar to one shown in FIG.9 in that the conductive bumps 8 a that penetrate through the insulatingboard 5 is directly formed on the resistive element 3. However, in thecase shown in FIG. 11, the conductive bumps 8 a are used, not as thelead wire, as heat conductor to the resistive element 3. The conductivebump 8 a works as a heat conductive bridge with the wiring pattern 1 con a rear surface side of the resistive element 3. One resistive element3 may be provided with a plurality of the conductive bumps 8 a.

[0133] In a resistor that is configured so as to have the conductivebumps 8 a for heat conduction, Joule heat that is generated due to theresistor may be efficiently dissipated from both surfaces of the wiringboard by use of the conductive bumps 8 a and the wiring pattern 1 c asheat-sink. Accordingly, since the resistor is increased in its powerrating, thereby a degree of freedom in circuit designing applied for thewiring board may be advantageously improved.

[0134]FIG. 12A and FIG. 12B are partial sectional views for explainingone example of a double-sided wiring board fabricated according to thefabricating method according to still another embodiment of the presentinvention. FIG. 12A shows an intermediate stage to a state shown in FIG.12B. Furthermore, the constituent elements that are already explainedare provided with the same reference numerals.

[0135] The double-sided wiring board 7 d is different from one shown inFIG. 1A and FIG. 1B in that the pattern 1 a and an electrical conductor35 formed from the conductive paste are used as both end electrodes ofthe dielectrics 2.

[0136] In order to fabricate a double-sided wiring board in such aconfiguration, first, as shown in FIG. 12A, after dielectrics 2 iscoated/formed on a metal foil 1, a conductive paste to be an electricalconductor 35 is coated including on the dielectrics 2 and extending ontothe metal foil 1. In the coating, a method identical to that used in thecoating of the dielectric paste to be the dielectrics 2 may be utilized.Treatment such as predetermined drying and so on is applied to thecoated conductive paste. Then, the metal foil 1 is used in place of thecoated/formed metal foil 4 shown in FIG. 1B upper side or FIG. 2B upperside and laminated. By further patterning the metal foils 1 on bothsides, the double-sided wiring board 7 d as shown in FIG. 12B may beobtained (in a strict sense, since there are the conductive bumps 8 inFIG. 12B, it shows a case applied to the case shown in FIG. 2B. However,the conductive bump 8 is not indispensable).

[0137] In a structure around the dielectrics 2 like this, since thepattern 1 a and the electrical conductor 35 sandwich the dielectrics 2and form a so-called parallel plate capacitor, a capacitor having highercapacitance may be formed. Furthermore, all of the already explainedimprovement effect as the passive element and wiring board ismaintained.

[0138]FIG. 13A and FIG. 13B are partial sectional views for explaininganother example to one example shown in FIG. 12A and FIG. 12B. FIG. 13Ashows an intermediate stage to a state shown in FIG. 13B. Furthermore,the constituent elements that are already explained are provided withthe same reference numerals.

[0139] The double-sided wiring board 7 e is one in which theaforementioned parallel plate capacitor structure is further activelyformed. Due to the lamination like this, a capacitor having highercapacitance may be formed.

[0140] Specifically, as shown in FIG. 13A, first, dielectrics 26 iscoated/formed on a metal foil 1 followed by coating a conductive pasteto be an electrical conductor 36 so as to include on the dielectrics 26and extend onto the metal foil 1. After the coating, processes such aspredetermined drying and so on are performed. Next, a dielectric pasteto be the dielectrics 27 is coated so as to include on the electricalconductor 36 and come into contact with the dielectrics 26. After thecoating, processes such as predetermined drying and so on are performed.Next, the conductive paste to be an electrical conductor 38 is coated soas to include on the dielectrics 27, not to come into contact with theelectrical conductor 36, and to extend onto the metal foil 1. After thecoating, processes such as predetermined drying and so on are performed.

[0141] Furthermore, the dielectric paste to be dielectrics 28 is coatedso as to include on the electrical conductor 38 and come into contactwith the dielectric 27. After the coating, processes such aspredetermined drying and so on are performed. Next, a conductive pasteto be an electrical conductor 37 is coated so as to include on thedielectrics 28, not to come into contact with the electrical conductor38, and to come into contact with the electrical conductor 36. After thecoating, processes such as predetermined drying and so on are performed.The coating of the dielectric paste to be individual dielectrics 26, 27and 28, and the coating of the conductive paste to be individualelectrical conductors 36, 37 and 38 are performed similarly to the casesof the dielectrics 2 and the electrical conductor 35 in the embodimentshown in, for instance, FIG. 12A and FIG. 12B.

[0142] Then, the metal foil 1 is used in place of the coated/formedmetal foil 4 shown in FIG. 1B upper side or FIG. 2B upper side and islaminated. Furthermore, by patterning the metal foils 1 on both sides, adouble-sided wiring board 7 e as shown in FIG. 13B may be obtained(since there are the conductive bumps 8 in FIG. 13B, in a strict sense,it shows a case applied to the case shown in FIG. 2B. However, theconductive bumps 8 are not indispensable). The patterning of the metalfoil 1 is performed so that as one electrode a pattern that occupiesalmost on the dielectrics 26 and comes into contact also with theelectrical conductor 38 may exist, and as another electrode a patternhaving an electrical continuity with electrical conductors 36 and 37 mayexist.

[0143] A capacitor due to such lamination may enable to realize afurther higher capacitance by further performing similar lamination.Furthermore, all of the aforementioned improvement effect as the passiveelement and the wiring board is maintained.

[0144] Although the above-explained examples due to FIGS. 9 through 13Bare of the cases of the double-sided wiring board, it is obvious thatouter wiring layers in the four-layered wiring boards (or theabove-explained three-layered wiring boards) as shown in FIG. 6 and FIG.7 may allow to form the above-explained passive elements. Furthermore,the situations are identical also in the case of a multi-layered,exceeding four layers, wiring board.

[0145]FIG. 15A and FIG. 15B are diagrams for explaining one example of afour-layered wiring board fabricated according to the fabricating methodaccording to still another embodiment of the present invention. FIG. 15Ais a sectional view and FIG. 15B is a top view thereof. Theaforementioned constituent numerals are given the same referencenumerals.

[0146] The four-layered wiring board is different from one shown in FIG.6 and FIG. 7 in that there are formed magnetically permeable bumps 8Aand 9A that, respectively, penetrate through insulating boards 5 and 51and these magnetically permeable bumps 8A and 9A are in contact in apenetrating direction. Furthermore, patterns 1 a and 1 b are patterned,respectively, as shown in FIG. 15B, so as to surround the magneticallypermeable bumps 8A and 9A and, as shown in FIG. 15A, the conductivebumps 8 and 9 bring ambient patterns into an electrical continuity in avertical direction.

[0147] That is, the magnetically permeable bumps 8A and 9A work as acore of an inductor, and each patterns 1 a and 1 b work as a helicalinductor coil as a whole. In thus structured inductor, since themagnetically permeable material is used as a core and a coil is realizedas a helical coil around the core, an inductance value may be increased.It is obvious that the inductor due to such a core and helical structureis, without restricting to such the four-layered wiring board, may beconfigured similarly even in a double-sided wiring board, three-layeredwiring board and multi-layered, exceeding four layers, wiring board.

[0148] In order to fabricate such the inductor that is incorporated in afour-layered wiring board, first, when a double-sided wiring board as acore wiring board is fabricated, in place of the coated/formed metalfoil 4 in FIG. 2B upper side, a magnetically permeable bump formed metalfoil fabricated according to the similar knack as the conductive bumpformed metal foil 4 a is used.

[0149] A magnetically permeable bump 8A may be formed on a placenecessary as a wiring board on the coated/formed metal foil 4 by meansof, for instance, screen printing. For this, as a magnetically permeablepaste, for instance, one in which magnetically permeable material powder(for instance, ferrite powder) is dispersed in a paste-like resinfollowed by mingling a volatile solvent is prepared, and this is coatedby means of screen-printing on the metal foil 4. The magneticallypermeable bump 8A is necessary to have a height enough to penetratethrough the insulating board 5. Accordingly, when one timescreen-printing cannot give a necessary height, screen-printing isrepeated a plurality of times to add height in a height direction whiledisposing a drying process between the screen-printings, and therebyforming into a substantially conical shape as a whole.

[0150] Then, following the above, processes up to one shown in FIG. 2Blower side are implemented. According to the processes up to this one,first, in the double-sided wiring board, an inductor due to a helicalstructure may be obtained.

[0151] Furthermore, in fabricating in a four-layered wiring board, inplace of the metal foil 1 in FIG. 6 upper side, a metal foil providedwith the magnetically permeable bump 9A thereon is used (a surface onwhich the magnetically permeable bump 9A is formed is directeddownward). In addition, in place of the wiring board material 71 in FIG.6 upper side, one in which the conductive bump 9 is formed on one side(top surface in the figure) of the double-sided wiring board includingthe aforementioned magnetically permeable bump 8A, and the magneticallypermeable bump 9A is formed on the other surface is used. Themagnetically permeable bump 9A can be formed similarly to the above.

[0152] Thereafter, the processes up to one shown in FIG. 6B lower sideare performed. Thereby, an inductor due to a helical structure in whichall layers of a four-layered wiring layer are used as coil can beobtained. Furthermore, by performing similarly, an inductor due to ahelical structure in which all layers of an N-layered wiring layer areused as coil can be obtained.

[0153]FIG. 16A and FIG. 16B are diagrams for explaining another exampleto one example shown in FIG. 15A and FIG. 15B. FIG. 16A is a sectionalview thereof and FIG. 16B is a top view thereof. The aforementionedconstituent elements are given the same reference numerals.

[0154] This four-layered wiring board is different from one shown inFIG. 15A and FIG. 15B in that a magnetically permeable pillared body 82that penetrates through the insulating boards 5 and 51 is used in placeof the magnetically permeable bumps 8A and 9A of the four-layered wiringboard shown in FIG. 15A and FIG. 15B.

[0155] In this case too, the magnetically permeable pillared body 82works as a core of an inductor, and each patterns 1 a and 1 b work as ahelical inductor coil as a whole. Accordingly, similarly to the above,an inductance value may be increased. It is obvious that an inductor dueto such a core of the magnetically permeable pillared body 82 and ahelical structure, without restricting to such a four-layered wiringboard, may be configured similarly even in a double-sided wiring board,three-layered wiring board, and multi-layered, exceeding four layers,wiring board.

[0156] In order to fabricate such an inductor incorporated infour-layered wiring board, a four-layered wiring board that hasundergone the process shown in FIG. 6 lower side may be provided with athrough-hole 81, and the formed through-hole 81 may be filled in with amagnetically permeable material. Similarly, a multi-layered, exceedingfour layers, wiring board also, after a multi-layered wiring boardhaving finally needed layers has been formed, may be provided with athrough-hole, and the formed through-hole may be filled in with amagnetically permeable material. As a magnetically permeable material,the magnetically permeable material as mentioned above may be used, orpreviously solidified magnetically permeable pillared body may beinserted and fixed.

[0157] The present invention has been described with reference tocertain preferred embodiments, but it will be understood that variationsand modifications can be made within the spirit and scope of theinvention.

What is claimed is:
 1. A method for fabricating a wiring board providedwith a passive element, comprising: coating a resistive paste and/or adielectric paste on at least any one of first surfaces of a first metalfoil and a second metal foil each of which has the first surface and asecond surface; arranging an insulating board having thermo-plasticityand thermo-setting properties so as to face the first surface of thefirst metal foil, and arranging the first surface side of the secondmetal foil so as to face a surface different from a surface to which thefirst metal foil faces of the insulating board; forming a double-sidedwiring board by stacking, pressurizing and heating three, that is, thearranged first metal foil, insulating board, and second metal foil tointegrate these; and patterning the first metal foil and/or the secondmetal foil of the formed double-sided wiring board.
 2. A method forfabricating a wiring board provided with a passive element as set forthin claim 1, further comprising: forming a substantially conicalconductive bump on the first surface of the first metal foil; whereinthe forming a double-sided wiring board is performed so that the formedconductive bump penetrates through the insulating board and establishesan electrical contact with the second metal foil.
 3. A method forfabricating a wiring board provided with a passive element as set forthin claim 1: wherein the patterning the first metal foil and/or thesecond metal foil includes formation of an inductor that is vorticallyformed due to a pattern and/or a loop antenna that is formed loop-likedue to a pattern.
 4. A method for fabricating a wiring board providedwith a passive element as set forth in claim 1, further comprising:trimming a resistor formed from the resistive paste by use of thepatterned first metal foil and/or the patterned second metal foil as anelectrode.
 5. A method for fabricating a wiring board provided with apassive element as set forth in claim 1: wherein the coating theresistive paste and/or the dielectric paste includes removing aperiphery portion thereof after the coating.
 6. A method for fabricatinga wiring board provided with a passive element as set forth in claim 1,further comprising: forming a substantially conical conductive bump on afirst surface of a third metal foil having the first surface and asecond surface; arranging a second insulating board havingthermo-plasticity and thermosetting properties so as to face the firstsurface of the third metal foil, and arranging the first metal foil sideof the double-sided wiring board so as to face a surface different froma surface that faces the third metal foil of the second insulatingboard; forming a three-layered wiring board by stacking, pressurizingand heating three, that is, the arranged third metal foil, secondinsulating board, and double-sided wiring board to integrate these sothat the conductive bump formed on the third metal foil penetratesthrough the second insulating board and establishes an electricalcontact with the first metal foil; and patterning the third metal foilof the formed three-layered wiring board.
 7. A method for fabricating awiring board provided with a passive element as set forth in claim 6:wherein the patterning the third metal foil includes formation of aninductor that is vortically formed due to a pattern and/or a loopantenna that is formed loop-like due to a pattern.
 8. A method forfabricating a wiring board provided with a passive element as set forthin claim 1, further comprising: coating a resistive paste and/or adielectric paste on a first surface of a third metal foil having thefirst surface and a second surface; forming a substantially conicalconductive bump on the first surface of the third metal foil; arranginga second insulating board having thermo-plasticity and thermosettingproperties so as to face the first surface of the third metal foil, andarranging a first metal foil side of the double-sided wiring board so asto face a surface different from a surface that faces the third metalfoil of the second insulating board; forming a three-layered wiringboard by stacking, pressurizing and heating three, that is, the arrangedthird metal foil, second insulating board, and double-sided wiring boardto integrate these so that the conductive bump formed on the third metalfoil penetrates through the second insulating board and establishes anelectrical contact with the first metal foil; and patterning the thirdmetal foil of the formed three-layered wiring board.
 9. A method forfabricating a wiring board provided with a passive element as set forthin claim 8: wherein the patterning the third metal foil includesformation of an inductor that is vortically formed due to a patternand/or a loop antenna that is formed loop-like due to a pattern.
 10. Amethod for fabricating a wiring board provided with a passive element asset forth in claim 8: wherein the coating a resistive paste and/or adielectric paste on the first surface of the third metal foil includesremoving a periphery portion thereof after the coating.
 11. A method forfabricating a wiring board provided with a passive element as set forthin claim 1, further comprising: forming a substantially conicalconductive bump on the second surface of the second metal foil of theformed double-sided wiring board; arranging a second insulating boardhaving thermo-plasticity and thermosetting properties so as to face aside on which the conductive bump of the double-sided wiring board isformed, and arranging a third metal foil so as to face a surfacedifferent from a surface that faces the double-sided wiring board of thesecond insulating board; forming a three-layered wiring board bystacking, pressurizing and heating three, that is, the arrangeddouble-sided wiring board, second insulating board, and third metal foilto integrate these so that the conductive bump formed on thedouble-sided wiring board penetrates through the second insulating boardand establishes an electrical contact with the third metal foil; andpatterning the third metal foil of the formed three-layered wiringboard.
 12. A method for fabricating a wiring board provided with apassive element as set forth in claim 11: wherein the patterning thethird metal foil includes formation of an inductor that is vorticallyformed due to a pattern and/or a loop antenna that is formed loop-likedue to a pattern.
 13. A method for fabricating a wiring board providedwith a passive element as set forth in claim 1, further comprising:coating a resistive paste and/or a dielectric paste on a first surfaceof a third metal foil having the first surface and a second surface;forming a substantially conical conductive bump on the second surface ofthe second metal foil of the formed double-sided wiring board; arranginga second insulating board having thermo-plasticity and thermosettingproperties so as to face a side on which the conductive bump of thedouble-sided wiring board is formed, and arranging the first surfaceside of the third metal foil so as to face a surface different from asurface that faces the double-sided wiring board of the secondinsulating board; forming a three-layered wiring board by stacking,pressurizing and heating three, that is, the arranged double-sidedwiring board, second insulating board, and third metal foil to integratethese so that the conductive bump formed on the double-sided wiringboard penetrates through the second insulating board and establishes anelectrical contact with the third metal foil; and patterning the thirdmetal foil of the formed three-layered wiring board.
 14. A method forfabricating a wiring board provided with a passive element as set forthin claim 13: wherein the patterning the third metal foil includesformation of an inductor that is vortically formed due to a patternand/or a loop antenna that is formed loop-like due to a pattern.
 15. Amethod for fabricating a wiring board provided with a passive element asset forth in claim 13: wherein the coating a resistive paste and/or adielectric paste on the first surface of the third metal foil includesremoving a periphery portion thereof after the coating.
 16. A method forfabricating a wiring board provided with a passive element as set forthin claim 1, further comprising: forming a substantially conicalconductive bump on a first surface of a third metal foil having thefirst surface and a second surface; forming a substantially conicalsecond conductive bump on the second surface of the second metal foil ofthe formed double-sided wiring board; arranging a second insulatingboard having thermo-plasticity and thermosetting properties so as toface the first surface of the third metal foil, arranging the firstmetal foil side of the double-sided wiring board so as to face a surfacedifferent from a surface to which the third metal foil faces of thesecond insulating board, arranging a third insulating board havingthermo-plasticity and thermosetting properties so as to face a side onwhich the second conductive bump is formed of the double-sided wiringboard, and arranging a fourth metal foil so as to face a surfacedifferent from a surface that faces the double-sided wiring board of thethird insulating board; forming a four-layered wiring board by stacking,pressurizing and heating five, that is, the arranged third metal foil,second insulating board, double-sided wiring board, third insulatingboard, and fourth metal foil to integrate these so that the conductivebump formed on the third metal foil penetrates through the secondinsulating board and establishes an electrical contact with the firstmetal foil and the second conductive bump formed on the double-sidedwiring board penetrates through the third insulating board andestablishes an electrical contact with the fourth metal foil; andpatterning the third metal foil and/or the fourth metal foil of theformed four-layered wiring board.
 17. A method for fabricating a wiringboard provided with a passive element as set forth in claim 16: whereinthe patterning the third metal foil and/or the fourth metal foil includeformation an inductor that is vortically formed due to a pattern and/ora loop antenna that is formed loop-like due to a pattern.
 18. A methodfor fabricating a wiring board provided with a passive element as setforth in claim 1, further comprising: coating a resistive paste and/or adielectric paste on at least any one or first surfaces of a third andfourth metal foils each of which has the first surface and a secondsurface; forming a substantially conical conductive bump on the firstsurface of the third metal foil; forming a substantially conical secondconductive bump on the second surface of the second metal foil of theformed double-sided wiring board; arranging a second insulating boardhaving thermo-plasticity and thermosetting properties so as to face thefirst surface of the third metal foil, arranging the first metal foilside of the double-sided wiring board so as to face a surface differentfrom a surface to which the third metal foil faces of the secondinsulating board, arranging a third insulating board havingthermo-plasticity and thermosetting properties so as to face a side onwhich the second conductive bump is formed of the double-sided wiringboard, and arranging the first surface side of the fourth metal foil soas to face a surface different from a surface that faces thedouble-sided wiring board of the third insulating board; forming afour-layered wiring board by stacking, pressurizing and heating five,that is, the arranged third metal foil, second insulating board,double-sided wiring board, third insulating board, and fourth metal foilto integrate these so that the conductive bump formed on the third metalfoil penetrates through the second insulating board and establishes anelectrical contact with the first metal foil and the second conductivebump formed on the double-sided wiring board penetrates through thethird insulating board and establishes an electrical contact with thefourth metal foil; and patterning the third metal foil and/or the fourthmetal foil of the formed four layered wiring board.
 19. A method forfabricating a wiring board provided with a passive element as set forthin claim 18: wherein the patterning the third metal foil and/or thefourth metal foil includes formation of an inductor that is vorticallyformed due to a pattern and/or a loop antenna that is formed loop-likedue to a pattern.
 20. A method for fabricating a wiring board providedwith a passive element as set forth in claim 18: wherein the coating aresistive paste and/or a dielectric paste on at least any one of thefirst surfaces of the third and fourth metal foils includes removing aperiphery portion thereof after the coating.
 21. A method forfabricating a wiring board provided with a passive element, comprising:coating a resistive paste on a first surface of at least a first metalfoil of the first metal foil and a second metal foil each of which has afirst surface and a second surface; forming a substantially conicalconductive bump on a resistive element formed of the coated resistivepaste; arranging an insulating board having thermo-plasticity andthermosetting properties so as to face the first surface of the firstmetal foil, and arranging the first surface of the second metal foil soas to face a surface different from a surface to which the first metalfoil faces of the insulating board; forming a double-sided wiring boardby stacking, pressurizing and heating three, that is, the arranged firstmetal foil, insulating board, and second metal foil to integrate theseso that the formed conductive bump penetrates through the insulatingboard and establishes an electrical contact and/or a heat conductivecontact with the second metal foil; and patterning the first metal foiland the second metal foil of the formed double-sided wiring board.
 22. Amethod for fabricating a wiring board provided with a passive element,comprising: coating a dielectric paste on a first surface of at least asecond metal foil of a first metal foil and the second metal foil eachof which has a first surface and a second surface; coating a conductivepaste so as to include on the coated dielectric paste and extend ontothe first surface on which the dielectric paste is coated; arranging aninsulating board having thermo-plasticity and thermosetting propertiesso as to face the first surface of the first metal foil, and arrangingthe first surface of the second metal foil so as to face a surfacedifferent from a surface to which the first metal foil faces of theinsulating board; forming a double-sided wiring board by stacking,pressurizing and heating three, that is, the arranged first metal foil,insulating board, and second metal foil to integrate these; andpatterning at least the second metal foil of the formed double-sidedwiring board.
 23. A method for fabricating a wiring board provided witha passive element, comprising: coating a dielectric paste on a firstsurface of at least a second metal foil of a first metal foil and thesecond metal foil each of which has a first surface and a secondsurface; coating a first conductive paste so as to include on the coateddielectric paste and extend onto the first surface on which thedielectric paste is coated; coating a second dielectric paste so as toinclude on the coated first conductive paste; coating a secondconductive paste so as to include on the coated second dielectric paste,to extend onto the first surface on which the second dielectric paste iscoated, and not to come into contact with the first conductive paste;arranging an insulating board having thermo-plasticity and thermosettingproperties so as to face the first surface of the first metal foil, andarranging the first surface of the second metal foil so as to face asurface different from a surface to which the first metal foil faces ofthe insulating board; forming a double-sided wiring board by stacking,pressurizing and heating three, that is, the arranged first metal foil,insulating board, and second metal foil to integrate these; andpatterning at least the second metal foil of the formed double-sidedwiring board.
 24. A method for fabricating a wiring board provided witha passive element, comprising: forming a substantially conicalconductive bump on a first surface of a first metal foil having thefirst surface and a second surface; forming a substantially conicalmagnetically permeable bump on a first surface of a second metal foilhaving the first surface and a second surface; arranging an insulatingboard having thermo-plasticity and thermosetting properties so as toface the first surface of the first metal foil, and arranging the firstsurface side of the second metal foil so as to face a surface differentfrom a surface to which the first metal foil faces of the insulatingboard; forming a double-sided wiring board by stacking, pressurizing andheating three, that is, the arranged first metal foil, insulating board,and second metal foil to integrate these so that the formed conductivebump and magnetically permeable bump penetrate through the insulatingboard and establish a contact with the first/second metal foil; andpatterning the first metal foil and the second metal foil of the formeddouble-sided wiring board.
 25. A method for fabricating a wiring boardprovided with a passive element as set forth in claim 24, furthercomprising: forming a substantially conical second conductive bump on afirst surface of a third metal foil having the first surface and asecond surface; forming a substantially conical second magneticallypermeable bump on a first surface of a fourth metal foil having thefirst surface and a second surface; forming a substantially conicalthird conductive bump on the second surface of the second metal foil ofthe formed double-sided wiring board; forming a substantially conicalthird magnetically permeable bump on a surface on the first metal foilside of the formed double-sided wiring board; arranging a secondinsulating board having thermo-plasticity and thermosetting propertiesso as to face the first surface of the third metal foil, arranging afirst metal foil side of the double-sided wiring board so as to face asurface different from a surface to which the third metal foil faces ofthe second insulating board, arranging a third insulating board havingthermo-plasticity and thermosetting properties so as to face a side onwhich the third conductive bump is formed of the double-sided wiringboard, and arranging the first surface side of the fourth metal foil soas to face a surface different from a surface that faces thedouble-sided wiring board of the third insulating board; forming afour-layered wiring board by stacking, pressurizing and heating five,that is, the arranged third metal foil, second insulating board,double-sided wiring board, third insulating board, and fourth metal foilto integrate these so that the second conductive bump formed on thethird metal foil penetrates through the second insulating board andestablishes an electrical contact with the first metal foil, the secondmagnetically permeable bump formed on the double-sided wiring boardpenetrates through the second insulating board and establishes a contactwith the third metal foil, the third conductive bump formed on thedouble-sided wiring board penetrates through the third insulating boardand establishes an electrical contact with the fourth metal foil, andthe third magnetically permeable bump formed on the fourth metal foilpenetrates through the third insulating board and establishes a contactwith a surface on a side of the second metal foil of the double-sidedwiring board; and patterning the third metal foil and the fourth metalfoil of the formed four-layered wiring board.
 26. A method forfabricating a wiring board provided with a passive element as set forthin claim 2, further comprising: forming a through-hole in the formeddouble-sided wiring board; and filling a magnetically permeable materialin the formed through-hole.
 27. A method for fabricating a wiring boardprovided with a passive element as set forth in claim 1 furthercomprising forming a substantially conical conductive bump on the firstsurface of the first metal foil, wherein the forming a double-sidedwiring board is performed so that the formed conductive bump penetratesthrough the insulating board and establishes an electrical contact withthe second metal foil, the method further comprising: forming asubstantially conical second conductive bump on a first surface of athird metal foil having the first surface and a second surface; forminga substantially conical third conductive bump on the second surface ofthe second metal foil of the formed double-sided wiring board; arranginga second insulating board having thermo-plasticity and thermosettingproperties so as to face the first surface of the third metal foil,arranging the first metal foil side of the double-sided wiring board soas to face a surface different from a surface to which the third metalfoil faces of the second insulating board, arranging a third insulatingboard having thermo-plasticity and thermosetting properties so as toface a side on which the third conductive bump is formed of thedouble-sided wiring board, and arranging the fourth metal foil so as toface a surface different from a surface that faces the double-sidedwiring board of the third insulating board; forming a four-layeredwiring board by stacking, pressurizing and heating five, that is, thearranged third metal foil, second insulating board, double-sided wiringboard, third insulating board, and fourth metal foil to integrate theseso that the second conductive bump formed on the third metal foilpenetrates through the second insulating board and establishes anelectrical contact with the first metal foil, and the third conductivebump formed on the double-sided wiring board penetrates through thethird insulating board and establishes an electrical contact with thefourth metal foil; patterning the third metal foil and the fourth metalfoil of the formed four-layered wiring board; forming a through-hole inthe formed four-layered wiring board; and filling a magneticallypermeable material in the formed through-hole.
 28. A wiring boardprovided with a passive element, comprising: an insulating board havinga first surface and a second surface; a layered resistive element and/ora layered dielectrics disposed on the first surface and/or the secondsurface of the insulating board so as to sink in a thickness directionof the insulating board; and a first wiring layer and a second wiringlayer that are, respectively, disposed on the first surface and thesecond surface of the insulating board, and each of which has aconnection with the layered resistive element and/or the layereddielectrics disposed on the corresponding first/second surface.
 29. Awiring board provided with a passive element as set forth in claim 28,further comprising: a conductive bump that penetrates through theinsulating board; wherein each of the first and second wiring layers hasan electrical connection with the conductive bump.
 30. A wiring boardprovided with a passive element as set forth in claim 28: wherein atleast one of the first and second wiring layers has an inductor that isvortically formed due to a pattern and/or a loop antenna that is formedloop-like due to a pattern.
 31. A wiring board provided with a passiveelement as set forth in claim 28, further comprising: a secondinsulating board disposed in contact with the first wiring layer side ofthe insulating board; a conductive bump that penetrates through thesecond insulating board; and a third wiring layer disposed on a sidedifferent from the insulating board side of the second insulating board;wherein the first wiring layer of the insulating board is disposed so asto sink in a thickness direction of the second insulating board; andeach of the first and third wiring layers has an electrical connectionwith the conductive bump.
 32. A wiring board provided with a passiveelement as set forth in claim 31, further comprising: a second layeredresistive element and/or a second layered dielectrics disposed on thethird wiring layer side of the second insulating board so as to sink ina thickness direction of the second insulating board; wherein the thirdwiring layer has a connection with the second layered resistiveelement/the second layered dielectrics.
 33. A wiring board provided witha passive element as set forth in claim 31: wherein the third wiringlayer has an inductor that is vortically formed due to a pattern and/ora loop antenna that is formed loop-like due to a pattern.
 34. A wiringboard provided with a passive element as set forth in claim 31, furthercomprising: a third insulating board disposed in contact with the secondwiring layer side of the insulating board; a second conductive bump thatpenetrates through the third insulating board; and a fourth wiring layerdisposed on a side different from the insulating board side of the thirdinsulating board; wherein the second wiring layer of the insulatingboard is disposed so as to sink in a thickness direction of the thirdinsulating board; and each of the second and fourth wiring layers has anelectrical connection with the second conductive bump.
 35. A wiringboard provided with a passive element as set forth in claim 34, furthercomprising: a second layered resistive element and/or a second layereddielectrics disposed on the fourth wiring layer side of the thirdinsulating board so as to sink in a thickness direction of the thirdinsulating board; wherein the fourth wiring layer has a connection withthe second layered resistive element/the second layered dielectrics. 36.A wiring board provided with a passive element as set forth in claim 34:wherein the fourth wiring layer has an inductor that is vorticallyformed due to a pattern and/or a loop antenna that is formed loop-likedue to a pattern.
 37. A wiring board provided with a passive element,comprising: an insulating board having a first surface and a secondsurface; a layered resistive element disposed on the second surface ofthe insulating board so as to sink in a thickness direction of theinsulating board; a first and second wiring layers disposed on the firstsurface and second surface of the insulating board, respectively; and aconductive bump that penetrates through the insulating board and is inan electrical connection and/or a heat conductive connection with thelayered resistive element and the first wiring layer.
 38. A wiring boardprovided with a passive element, comprising: an insulating board havinga first surface and a second surface; a layered electrical conductordisposed on the second surface of the insulating board so as to sink ina thickness direction of the insulating board; a layered dielectricsdisposed in contact with a part of a top surface of the layeredelectrical conductor so as to sink in a thickness direction of theinsulating board; and a wiring layer that is disposed on the secondsurface of the insulating board and has individual connections with thelayered electrical conductor and the layered dielectrics.
 39. A wiringboard provided with a passive element as set forth in claim 38, furthercomprising: a second layered dielectrics disposed under a bottom surfaceof the layered electrical conductor; and a second electrical conductorthat is disposed containing under a bottom surface of the second layereddielectrics and is in connection with the wiring layer.
 40. A wiringboard provided with a passive element, comprising: an insulating boardhaving a first surface and a second surface; a first and second wiringlayers, respectively, disposed on the first surface and the secondsurface of the insulating board; a conductive bump that penetratesthrough the insulating board and is in an electrical connection with thefirst wiring layer and the second wiring layer; and a magneticallypermeable bump that penetrates through the insulating board; wherein thefirst wiring layer has a first pattern that surrounds the magneticallypermeable bump; the second wiring layer has a second pattern thatsurrounds the magnetically permeable bump; and the first and secondpatterns are in continuity due to the conductive bump.
 41. A wiringboard provided with a passive element as set forth in claim 40, furthercomprising: a second insulating board disposed on the first wiring layerside of the insulating board; a third insulating board disposed on thesecond wiring layer side of the insulating board; a third wiring layerdisposed on a surface side different from the insulating board of thesecond insulating board; a fourth wiring layer disposed on a surfaceside different from the insulating board of the third insulating board;a second conductive bump that penetrates through the second insulatingboard and is brought into electrical connections with the first wiringlayer and the third wiring layer; a second magnetically permeable bumpthat penetrates through the second insulating board; a third conductivebump that penetrates through the third insulating board and is broughtinto electrical connections with the second wiring layer and the fourthwiring layer; and a third magnetically permeable bump that penetratesthrough the third insulating board; wherein the first wiring layer isdisposed so as to sink in a thickness direction of the second insulatingboard; the second wiring layer is disposed so as to sink in a thicknessdirection of the third insulating board; the magnetically permeablebump, the second magnetically permeable bump, and the third magneticallypermeable bump are disposed in series; the third wiring layer has athird pattern that surrounds the second magnetically permeable bump; thefourth wiring layer has a fourth pattern that surrounds the thirdmagnetically permeable bump; the first and third patterns are in anelectrical continuity due to the second conductive bump; and the secondand fourth patterns are in an electrical continuity due to the thirdconductive bump.
 42. A wiring board provided with a passive element asset forth in claim 41, comprising: a pillared body that has amagnetically permeable material and penetrates through the insulatingboard, the second insulating board, and the third insulating board inplace of the magnetically permeable bump, the second magneticallypermeable bump, and the third magnetically permeable bump.